The quarterback clocks in before most of his teammates for that matter.

With that work ethic and standout performances, Kaepernick has earned himself a third straight start at quarterback for San Francisco on Sunday at St. Louis.

"Kap's here before me. He's here lifting weights," Walker said.

Coach Jim Harbaugh made the announcement Wednesday that Kaepernick got the nod over Alex Smith after the second-year pro led the NFC West-leading Niners (8-2-1) to victories in the past two games, his first two NFL starts.

"The rationale is we have two quarterbacks that we feel great about as a starting quarterback," Harbaugh said. "Both have earned it, both deserve it
-- Alex over a long period of time, Colin by virtue of the last three games. It tips the scales. Colin we believe has the hot hand. We'll go with Colin. And we'll go with Alex. They're both our guys."

Yes, Harbaugh is still leaving open every possibility, saying it still could be a week-to-week decision. All Kaepernick knows is he will begin Sunday's game under center.

Harbaugh warned, "I wouldn't assume anything."

"To start talking about speculation or every permutation you could get into, we're not going to speculate on it," Harbaugh said. "We're worried about everything and we fear nothing."

The reigning NFL Coach of the Year told his players on the field at some point during Wednesday morning's walk-through practice.

Kaepernick has completed 48 of 74 passes for 680 yards and three touchdowns with one interception and was sacked six times. He has a 102.3 passer rating.

"I don't know if it's a hot hand. Whatever you want to call it. I'm just happy I get to go back out there," Kaepernick said. "It's a great chance to lead this team and show we're a great team and we can go into the playoffs."

Smith, the 2005 No. 1 overall draft pick, hardly looked happy on the sideline during Sunday's win over the Saints after being medically cleared from a concussion suffered in the first half of a 24-24 tie against St. Louis on Nov. 11.

"That's coach's decision," running back Frank Gore said. "He said before he's going to go with the hot hand, and he's sure that Kap's got the hot hand right now. I just feel we've got two good quarterbacks who can help us win. That's a plus for the team."

As the questions about his quarterback decision kept coming from every direction, Harbaugh repeatedly said, "I think I've covered and plowed that ground about as thoroughly as it can be plowed."

Losing his job is nothing new for Smith in what has been a roller coaster eight-year NFL career filled with promotions and demotions. Even after his last full game was an impressive win on Monday Night Football at Arizona on Oct. 29 that earned him NFC Offensive Player of the Week honors. In a near-perfect night, Smith completed 18 of 19 passes for 232 yards and three touchdowns without an interception. He had a 157.1 passer rating and connected with nine different receivers.

Smith bounced from starter to the bench throughout 2010 after coming into the year entrenched as the starter
-- and that's been his story each year except for during last year's turnaround season. He is 19-5-1 in two years playing for former NFL quarterback Harbaugh.

In the locker room, players have said all the right things: supporting both quarterbacks, while reiterating it is Harbaugh's call to make.

"It's getting very old. It's kind of taking away from what the Niners are doing, all this fuss about our quarterback situation," Walker said. "(Alex) definitely didn't lose his job. Kap is just playing well, so that's what I think you're seeing right now. A lot of guys on offense are feeding off it. So we're just going to go with Kap until Jim Harbaugh decides otherwise."

Walker knows it's probably not over yet, though, as Smith very well could get another shot sometime over the final five games.

Also Wednesday, Harbaugh said kicker David Akers is nursing an undisclosed injury, and that's why the 49ers worked out kickers Tuesday. Akers was later listed limited in practice because of a pelvis injury. He looked strong at the start of practice, kicking field goals from 50 yards and demonstrating ample leg strength and accuracy. He missed what would have been the game-winning field goal in overtime last time against the Rams, then missed one from 50 yards in the fourth quarter and had another blocked from 33 yards out Sunday at New Orleans. Akers was clipped by a Saints player after his fourth extra-point attempt in the third quarter but showed no visible signs of injury.

He has missed four of his last seven tries from 40 to 49 yards and eight of his last 21 overall. He ranks 29th in field-goal percentage at 70.4 after setting a single-season NFL record last season with 44 made field goals.

"David Akers is working through something and we want to make sure we have a Plan B," Harbaugh said.

NOTES: Walker didn't practice but said he expects to play against the Rams after bruising a hip and his ribs Sunday in the Superdome. ... In addressing the season-ending injuries of WR and return man Kyle Williams (knee) and RB Kendall Hunter (ankle), Harbaugh said, "The sad thing for all of us is two known friends and trusted agents, Kyle Williams and Kendall Hunter, are going to be out for the season." ... Also on Wednesday's practice report: LB Aldon Smith (shoulder) and S Darcel McBath (concussion).